


rule number one

by wincestjel



Series: rule number one & heartless, mindless monster [1]
Category: Supernatural
Genre: DeanCas - Freeform, Demon!Dean, Destiel - Freeform, Destiel One Shot, M/M, One Shot, demon!dean is hot, demon!dean x castiel, sue me
Language: English
Status: Completed
Published: 2018-09-18
Updated: 2018-09-18
Packaged: 2019-07-13 20:09:05
Rating: Not Rated
Warnings: Major Character Death
Chapters: 1
Words: 706
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16025099
Author URL: https://archiveofourown.org/users/wincestjel/pseuds/wincestjel
Summary: "i'm a demon, cas. and rule number one? demons lie."- AUish in which cas also fell for having relations with a human (Dean), and Dean never got rid of the mark so he's still a demon -





	rule number one

**Author's Note:**

> in which mr. demon!dean winchester pays his angel friend a visit

“Dean..” Cas breathed, his eyes roaming the once-hunter’s body. “You… Why have you come, Dean?”

Dean’s lips curled up into his trademark smirk, eyes flickering black. “To see you, of course, angel boy.”

“Dean, I'm sure you are aware I am no longer an angel.”

“You ain't a saint, either, Cas.” Dean chuckled. “Never been. Remember that night? Just us? Sammy was god knows where… the music..”

“Yes, Dean. I remember that night very clearly, thank you.” Cas grumbled, his eyes shut.

That night had been something else—Dean bursting into the motel room, piss drunk, Cas waiting for the boys like the obedient angel he was.

_“Hello, Dean. You.. don't look so good.” Castiel had murmured, as Dean was now in his face, their lips almost touching._

_“As my_ favorite _angel once said, ‘I found a liquor store, and I drank it.’” Dean’s words slurred together, his breath-reeking of alcohol--hot against Cas’ lips._

_“Dean..” Castiel would have liked to say he pushed the drunk man away, but he hardly tried. For so long, the angel had wanted this, wanted Dean._

_“I see the way you look at me, Cas.” Dean’s lips curled up._

_“Dean, you're drunk… You aren't thinking straight. Go to sleep…”_

_There was a moment of silence, then blue met green, and pink met pinker. The kiss was soft and cautious at first, and without Dean knowing, Cas used his ‘mojo’, as the hunter called it, to flush the alcohol from his system. When the kiss didn't stop, he finally relaxed, pushing Dean back onto his-or was it Sam’s?-bed, and it was all shy touches, soft gasps, quiet murmurs._

_The next morning Dean woke up, cold and alone, half naked, a roughly Cas-sized wrinkle in the sheets beside him. He knew what had happened, knew it was real._

To this day, that night still stuck out like a sore thumb, the memory more prominent than any others he had. He still remembered the way it felt, the intimacy,  _everything_.

And by the look on his face, Cas remembered it all too.

“We could do it again, you know. No punishment this time.” Dean stepped closer, his eyes flickering back to their usual, should-be-fictional green. His tongue flicked out over his lips, a deep chuckle coming from his chest.

“Dean, this isn't you.” Castiel looked to the ground, knowing as soon as he looked into Dean’s eyes he would break.

“It's as me as I’ll ever be, baby.” Dean chuckled again, that sick, cold, empty sound erupting from his chest. He curled his fingers under Castiel’s chin, smiling a little.

“ _Dean_..” Cas whispered, his eyes still shut.

“Cas, it's me, I swear..” Dean mumbled, voice softening.

The angel finally opened his eyes, letting out a soft gasp. Dean’s eyes were certainly, well, _Dean's eyes_. He bit his lip, trying to look away, but for the first time in a long time, they kissed. Softly at first, unsure. But when Dean let out a soft gasp of, “ _Cas_..” things took a turn, things grew more heated and their hands were on each other.

“Dean.. wait.” Cas mumbled, reluctantly pulling back. “I.. do you know what happened last time we…?”

“I know it's part of why you fell, Cas.” Dean said softly, sadly, wrapping his arms around Castiel’s waist, under his coat, and nuzzling the angel’s neck lightly. “I'm sorry..”

“It's.. not all your fault, Dean, but..” Cas turned, kissing Dean’s forehead lightly. “Do you… still love me? Like you used to?”

“Course I do, Cas.” Dean took Cas’ face in his hands, kissing him, smiling softly. “I love you.”

“I- I love you too, Dean.”

“One more thing, Cas?” Dean mumbled, pulling his arms back to his sides. He chuckled again, that same empty sound, his eyes flickering black and lips curling.

“Dean… what are you—?” Cas started, but was interrupted by a knife to the chest. “Dean!”

“I’m a demon, Cas.” Dean dug the blade in deeper, bright blue light pouring from Cas’ eyes and mouth, the eerie-yet-beautiful screech of an angel dying filling the small space. He pulled the angel blade, tucking it into his belt and watching as Castiel’s lifeless form fell limp.

“And rule number one? Demons lie.”

—fin


End file.
